I am like phil666, I run many vmware and VirtualPC Images of Windows in its' many incarnations.
I run WinXP SP1 on my laptop, W2K3 SP1 on my Server, and XP SP1 on a Drone Box, and I use the Live Version of Kubuntu Linux 5x (with KDE) for my Roaming and Tinkering, I have VMW and VPC Images of RedHat, SUSe and Mandrake Solaris 10 also. I do Desktop Support and try to stay current or be able to float an Image to immerse myself in my Users / Customers Environments as often as possible, or to test something in as well.